1. Field of the Invention
The present invention relates to a bearing configured to support a shaft for rotation about a predetermined rotational center axis and to be attachable to a member to which the bearing is to be mounted (hereinafter referred to as a “mount member”).
2. Description of the Related Art
Bearings are used in various portions of various apparatuses. With resent downsizing of various apparatuses and enhancement of their performances, demand has arisen for improvement of bearings, such as downsizing and strengthening of shaft-holding force.
For example, an image forming apparatus, such as a laser printer, uses a large number of relatively long rollers (longer than 210 mm, which is the width of an A4 sheet). When bearings which rotatably support such rollers cannot provide proper shaft-holding forces, malfunction may occur in an image forming operation. Meanwhile, increasing the sizes of bearings for strengthening their shaft-holding forces runs contrary to the recent demand for downsizing of image forming apparatuses.
Further, when a bearing is designed such that assembly or attachment of a shaft to the bearing becomes easier, in many cases, the shaft-holding force of the bearing decreases. Meanwhile, when an attempt is made to strengthen the bearing-holding force, in many cases, assembly of the shaft into the bearing becomes difficult.
Incidentally, various bearing structures are known (see, for example, Japanese Patent Application Laid-Open (kokai) No. H7-310735, the microfilm of Japanese Utility Model Application No. S62-111226 (Japanese Utility Model Application Laid-Open (kokai) No. S64-17024), the microfilm of Japanese Utility Model Application No. S55-29016 (Japanese Utility Model Application Laid-Open (kokai) No. S56-131019), and the microfilm of Japanese Utility Model Application No. S52-163277 (Japanese Utility Model Application Laid-Open (kokai) No. S54-88450).